trans-Di­aqua­tetrakis(3,5-di­methyl­pyrazole-N²)­nickel(II) dichloride

The X-ray structure analysis of [Ni(C₅H₈N₂)₄(H₂O)₂]Cl₂ was undertaken to elucidate the geometry around the Ni²⁺ ion. The molecule lies on a twofold axis which runs through the O-Ni-O atoms. The geometry around the Ni²⁺ ion is best described as slightly distorted tetragonal bipyramidal.

S1. Comment

In recent years we have investigated the coordination chemistry of metal complexes with N-containing heterocycles derivatives (Driessen et al., 1988; Małecka et al., 1998; Ochocki et al., 1990, 1992, 1997) because of expected pharmacological activity by analogy to cis platinum complexes (Hollis, 1989; Reedijk, 1996). Previous studies on this kind of complexes showed the significant role played in biological processes which is often related to their coordination ability towards transition metal ions (Ochocki et al., 1998). This work opens the studies on transition metal complexes with pyrazoles and their derivatives. On the other hand nickel is now recognized to be an essential element for bacteria, plants, animals and humans, since it plays an important role in catalytic activity of enzymes. \sch

The X-ray structure analysis of the title compound, (I), was undertaken to elucidate the geometry around the Ni²⁺ ion. The central ion Ni²⁺ of the complex is in a special position on the twofold axis running through atoms O1, Ni1 and O2. The Ni²⁺ ion is centered in slightly distorted octahedral environment. The basal plane is formed by N atoms of 3,5-dimethylpyrazole ligands, which is distorted with the tetrahedral angle [178.3 (1)°] [proposed by Holm & O'Connor (1971)]. The distortion of the local tetrahedral coordination is assigned in a bending angle of 179.4 (1)° (which shows how far the Ni²⁺ ion is shifted from the geometric centre of the tetrahedron). There is a net of hydrogen bonds (see table 2). Bond distances and angles in the phenyl and pyrazole rings are in a good agreement with expected values (Allen et al., 1987; Orpen et al., 1989).

The ORTEP drawing of the molecule with the atomic numbering scheme is given in Fig. 1.

Related literature

For related literature, see: Allen et al. (1987); Driessen et al. (1988); Hollis (1989); Holm & O'Connor (1971); Małecka et al. (1998); Ochocki et al. (1990, 1992, 1997, 1998); Orpen et al. (1989); Reedijk (1996).

S2. Experimental

The title compound was obtained by reaction of 3,5-dimethylpirazole with nickel(II) chloride hexahydrate (4:1 stoichiometric) in ethanol-water (4:1) solution. The light blue crystals were obtained by slow evaporation from the same solution.

Computing details

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1989a); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN (Molecular Structure Corporation, 1989b); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEX (McArdle, 1995); software used to prepare material for publication: PARST97 (Nardelli, 1996).

Figures

Fig. 1. ORTEP (McArdle, 1995) drawing of the molecule. Displacement ellipsoids are drawn at the 40% probability level.

trans diaqua [tetrakis(3,5-dimethylopyrazole- N²)] nickel (II) dichloride

Crystal data

[Ni(C5H8N2)4(H2O)2]Cl2	F(000) = 1160
Mr = 550.18	Dx = 1.302 Mg m^−3 Dm = 1.300 Mg m^−3 Dm measured by flotation in xylene, bromobenzene, toluene and heptane
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71069 Å
a = 10.505 (3) Å	Cell parameters from 25 reflections
b = 14.213 (2) Å	θ = 6.1–12.8°
c = 18.822 (3) Å	µ = 0.91 mm^−1
β = 92.77 (2)°	T = 293 K
V = 2807.1 (10) Å^3	Block, light blue
Z = 4	0.5 × 0.2 × 0.2 mm

Data collection

AFC5S Rigaku diffractometer	3056 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.024
Graphite monochromator	θmax = 32.6°, θmin = 3.6°
ω scan	h = 0→15
Absorption correction: analytical (de Meulenaer & Tompa, 1965)	k = 0→21
Tmin = 0.560, Tmax = 0.788	l = −28→28
5343 measured reflections	3 standard reflections every 150 min
5110 independent reflections	intensity decay: <2%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.057	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.171	w = 1/[σ^2(Fo^2) + (0.0852P)^2] where P = (Fo^2 + 2Fc^2)/3'
S = 1.05	(Δ/σ)max = 0.026
5109 reflections	Δρmax = 0.84 e Å^−3
185 parameters	Δρmin = −0.85 e Å^−3
0 restraints

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. All H-atoms from methyl groups constrained to their parent atoms as a rigid body SHELXL97 (Sheldrick, 1997). U(H71)=1.1 U_eqof its parent atom. U(H72)=1.1 U_eqof its parent atom. U(H73)=1.1 U_eqof its parent atom. U(H141)=1.1 U_eqof its parent atom. U(H142)=1.1 U_eqof its parent atom. U(H143)=1.1 U_eqof its parent atom.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Ni1	0.0000	0.58603 (3)	0.2500	0.03122 (14)
O1	0.0000	0.7315 (2)	0.2500	0.0457 (7)
H101	0.055 (3)	0.757 (2)	0.2574 (18)	0.044 (10)*
O2	0.0000	0.4404 (2)	0.2500	0.0454 (7)
H201	−0.049 (3)	0.411 (2)	0.259 (2)	0.051 (11)*
Cl3	0.74899 (8)	0.16394 (6)	0.72457 (5)	0.0598 (2)
N1	−0.2219 (2)	0.65599 (19)	0.32991 (15)	0.0494 (6)
H1	−0.232 (3)	0.695 (2)	0.2947 (17)	0.046 (9)*
N2	−0.1348 (2)	0.58546 (16)	0.32987 (11)	0.0391 (5)
C3	−0.1448 (3)	0.5412 (2)	0.39241 (15)	0.0462 (6)
C6	−0.0682 (4)	0.4573 (2)	0.41348 (17)	0.0576 (8)
H61	0.0172	0.4649	0.3983	0.118 (18)*
H62	−0.1057	0.4023	0.3915	0.087 (14)*
H63	−0.0663	0.4504	0.4643	0.079 (12)*
C4	−0.2371 (4)	0.5863 (3)	0.4314 (2)	0.0649 (10)
H4	−0.255 (4)	0.570 (3)	0.472 (2)	0.086 (14)*
C5	−0.2839 (4)	0.6593 (3)	0.3906 (2)	0.0645 (10)
C7	−0.3824 (5)	0.7338 (4)	0.4022 (3)	0.1036 (18)
H71	−0.3556	0.7921	0.3819	0.114*
H72	−0.3922	0.7419	0.4522	0.114*
H73	−0.4623	0.7149	0.3797	0.114*
N8	0.2494 (2)	0.52407 (19)	0.32034 (14)	0.0455 (6)
H8	0.251 (4)	0.491 (3)	0.289 (2)	0.064 (12)*
N9	0.1546 (2)	0.58818 (16)	0.32674 (11)	0.0381 (4)
C10	0.1828 (3)	0.6317 (2)	0.38899 (14)	0.0419 (6)
C13	0.1033 (4)	0.7092 (2)	0.41651 (17)	0.0543 (8)
H131	0.1043	0.7060	0.4675	0.105 (15)*
H132	0.0173	0.7028	0.3975	0.113 (17)*
H133	0.1371	0.7687	0.4023	0.101 (15)*
C11	0.2953 (3)	0.5942 (3)	0.42011 (18)	0.0585 (8)
H11	0.332 (4)	0.607 (3)	0.468 (2)	0.083 (13)*
C12	0.3338 (3)	0.5257 (3)	0.37614 (19)	0.0583 (8)
C14	0.4454 (4)	0.4591 (4)	0.3796 (3)	0.0948 (16)
H141	0.4206	0.4004	0.3578	0.104*
H142	0.4724	0.4484	0.4284	0.104*
H143	0.5144	0.4859	0.3548	0.104*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.0290 (2)	0.0265 (2)	0.0382 (2)	0.000	0.00162 (15)	0.000
O1	0.0356 (16)	0.0299 (14)	0.071 (2)	0.000	−0.0038 (15)	0.000
O2	0.0350 (15)	0.0282 (13)	0.074 (2)	0.000	0.0112 (14)	0.000
Cl3	0.0553 (5)	0.0515 (4)	0.0725 (5)	−0.0242 (4)	0.0004 (4)	0.0036 (4)
N1	0.0430 (13)	0.0451 (14)	0.0612 (15)	0.0064 (11)	0.0145 (11)	0.0062 (12)
N2	0.0380 (11)	0.0367 (11)	0.0429 (11)	0.0008 (9)	0.0044 (9)	0.0009 (9)
C3	0.0528 (17)	0.0440 (15)	0.0420 (14)	−0.0087 (13)	0.0042 (12)	−0.0016 (11)
C6	0.077 (2)	0.0492 (18)	0.0461 (16)	−0.0043 (17)	−0.0055 (15)	0.0078 (14)
C4	0.076 (2)	0.067 (2)	0.0550 (18)	−0.0077 (19)	0.0290 (17)	0.0025 (17)
C5	0.059 (2)	0.059 (2)	0.079 (2)	0.0036 (16)	0.0340 (18)	−0.0020 (17)
C7	0.089 (3)	0.091 (3)	0.137 (4)	0.027 (3)	0.062 (3)	−0.002 (3)
N8	0.0389 (12)	0.0455 (14)	0.0516 (14)	0.0076 (10)	−0.0040 (10)	−0.0097 (11)
N9	0.0339 (10)	0.0368 (11)	0.0433 (11)	0.0031 (9)	−0.0005 (8)	−0.0032 (9)
C10	0.0451 (14)	0.0386 (14)	0.0417 (13)	−0.0066 (11)	−0.0003 (11)	−0.0009 (11)
C13	0.066 (2)	0.0458 (17)	0.0510 (16)	0.0012 (15)	0.0023 (15)	−0.0100 (13)
C11	0.0568 (19)	0.064 (2)	0.0530 (17)	0.0001 (16)	−0.0160 (14)	−0.0083 (15)
C12	0.0442 (16)	0.060 (2)	0.069 (2)	0.0098 (15)	−0.0155 (14)	−0.0029 (16)
C14	0.063 (3)	0.102 (4)	0.115 (4)	0.035 (3)	−0.036 (2)	−0.022 (3)

Geometric parameters (Å, º)

Ni1—O1	2.068 (3)	C5—C7	1.502 (5)
Ni1—O2	2.070 (3)	C7—H71	0.9600
Ni1—N2^i	2.115 (2)	C7—H72	0.9600
Ni1—N2	2.115 (2)	C7—H73	0.9600
Ni1—N9	2.121 (2)	N8—C12	1.342 (4)
Ni1—N9^i	2.121 (2)	N8—N9	1.360 (3)
O1—H101	0.69 (3)	N8—H8	0.75 (4)
O2—H201	0.69 (3)	N9—C10	1.345 (3)
N1—C5	1.344 (4)	C10—C11	1.399 (4)
N1—N2	1.357 (3)	C10—C13	1.490 (4)
N1—H1	0.87 (3)	C13—H131	0.9600
N2—C3	1.343 (4)	C13—H132	0.9600
C3—C4	1.399 (5)	C13—H133	0.9600
C3—C6	1.482 (5)	C11—C12	1.353 (5)
C6—H61	0.9600	C11—H11	0.99 (4)
C6—H62	0.9600	C12—C14	1.506 (5)
C6—H63	0.9600	C14—H141	0.9600
C4—C5	1.368 (6)	C14—H142	0.9600
C4—H4	0.84 (4)	C14—H143	0.9600
O1—Ni1—O2	180.0	N1—C5—C7	120.9 (4)
O1—Ni1—N2^i	90.22 (6)	C4—C5—C7	133.3 (4)
O2—Ni1—N2^i	89.78 (6)	C5—C7—H71	109.5
O1—Ni1—N2	90.22 (6)	C5—C7—H72	109.5
O2—Ni1—N2	89.78 (6)	H71—C7—H72	109.5
N2^i—Ni1—N2	179.56 (13)	C5—C7—H73	109.5
O1—Ni1—N9	89.17 (6)	H71—C7—H73	109.5
O2—Ni1—N9	90.83 (6)	H72—C7—H73	109.5
N2^i—Ni1—N9	88.12 (8)	C12—N8—N9	112.2 (3)
N2—Ni1—N9	91.88 (8)	C12—N8—H8	126 (3)
O1—Ni1—N9^i	89.17 (6)	N9—N8—H8	122 (3)
O2—Ni1—N9^i	90.83 (6)	C10—N9—N8	104.7 (2)
N2^i—Ni1—N9^i	91.88 (8)	C10—N9—Ni1	136.82 (19)
N2—Ni1—N9^i	88.12 (8)	N8—N9—Ni1	118.04 (17)
N9—Ni1—N9^i	178.35 (12)	N9—C10—C11	109.6 (3)
Ni1—O1—H101	121 (3)	N9—C10—C13	122.6 (3)
Ni1—O2—H201	127 (3)	C11—C10—C13	127.8 (3)
C5—N1—N2	112.4 (3)	C10—C13—H131	109.5
C5—N1—H1	125 (2)	C10—C13—H132	109.5
N2—N1—H1	122 (2)	H131—C13—H132	109.5
C3—N2—N1	105.3 (2)	C10—C13—H133	109.5
C3—N2—Ni1	135.1 (2)	H131—C13—H133	109.5
N1—N2—Ni1	118.17 (17)	H132—C13—H133	109.5
N2—C3—C4	109.3 (3)	C12—C11—C10	106.8 (3)
N2—C3—C6	123.1 (3)	C12—C11—H11	126 (2)
C4—C3—C6	127.6 (3)	C10—C11—H11	127 (2)
C3—C6—H61	109.5	N8—C12—C11	106.6 (3)
C3—C6—H62	109.5	N8—C12—C14	120.4 (3)
H61—C6—H62	109.5	C11—C12—C14	133.0 (3)
C3—C6—H63	109.5	C12—C14—H141	109.5
H61—C6—H63	109.5	C12—C14—H142	109.5
H62—C6—H63	109.5	H141—C14—H142	109.5
C5—C4—C3	107.1 (3)	C12—C14—H143	109.5
C5—C4—H4	129 (3)	H141—C14—H143	109.5
C3—C4—H4	123 (3)	H142—C14—H143	109.5
N1—C5—C4	105.8 (3)

Symmetry code: (i) −x, y, −z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H101···Cl3^ii	0.69 (3)	2.35 (3)	3.044 (2)	175 (3)
O2—H201···Cl3^iii	0.69 (3)	2.39 (3)	3.065 (2)	166 (4)
N1—H1···Cl3^iv	0.87 (3)	2.40 (3)	3.242 (3)	164 (3)
N8—H8···Cl3^v	0.75 (4)	2.52 (4)	3.223 (3)	157 (4)

Symmetry codes: (ii) −x+1, −y+1, −z+1; (iii) −x+1/2, −y+1/2, −z+1; (iv) x−1, −y+1, z−1/2; (v) x−1/2, −y+1/2, z−1/2.